diff --git a/examples/Makefile b/examples/Makefile
index 0e74b74..9dfbbe1 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -7,7 +7,7 @@ INCLUDE_PATH	= ../include
 CFLAGS		+= -I$(INCLUDE_PATH)
 LDFLAGS		= -L../src -lskipstone
 
-EXAMPLES	= read music map test
+EXAMPLES	= read music map test queue
 
 RM		= /bin/rm
 
diff --git a/examples/queue.c b/examples/queue.c
new file mode 100644
index 0000000..1e139f2
--- /dev/null
+++ b/examples/queue.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <skipstone/queue.h>
+
+int main(int argc, char **argv) {
+    skipstone_queue *queue;
+    char *message;
+
+    if ((queue = skipstone_queue_new()) == NULL) {
+        perror("skipstone_queue_new()");
+
+        return 1;
+    }
+
+    skipstone_queue_push(queue, "poop");
+    skipstone_queue_pop(queue, &message);
+
+    printf("%s\n", message);
+
+    skipstone_queue_destroy(queue);
+
+    return 0;
+}
diff --git a/examples/queue.c-e b/examples/queue.c-e
new file mode 100644
index 0000000..1e139f2
--- /dev/null
+++ b/examples/queue.c-e
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <skipstone/queue.h>
+
+int main(int argc, char **argv) {
+    skipstone_queue *queue;
+    char *message;
+
+    if ((queue = skipstone_queue_new()) == NULL) {
+        perror("skipstone_queue_new()");
+
+        return 1;
+    }
+
+    skipstone_queue_push(queue, "poop");
+    skipstone_queue_pop(queue, &message);
+
+    printf("%s\n", message);
+
+    skipstone_queue_destroy(queue);
+
+    return 0;
+}
diff --git a/include/skipstone/queue.h b/include/skipstone/queue.h
index 825067f..c5b15d6 100644
--- a/include/skipstone/queue.h
+++ b/include/skipstone/queue.h
@@ -13,4 +13,6 @@ int skipstone_queue_push(skipstone_queue *queue, void *value);
 
 int skipstone_queue_pop(skipstone_queue *queue, void **value);
 
+void skipstone_queue_destroy(skipstone_queue *queue);
+
 #endif /* _SKIPSTONE_QUEUE_H */
diff --git a/src/message.c b/src/message.c
index f9754fc..8efb14f 100644
--- a/src/message.c
+++ b/src/message.c
@@ -19,7 +19,30 @@ struct _skipstone_message_service {
 };
 
 skipstone_message_service *skipstone_message_service_new() {
-    return (skipstone_message_service *)skipstone_map_new();
+    skipstone_message_service *service;
+
+    if ((service = malloc(sizeof(*service))) == NULL) {
+        goto error_malloc_service;
+    }
+
+    if ((service->endpoints = skipstone_map_new()) == NULL) {
+        goto error_map_new_endpoints;
+    }
+
+    if ((service->pending = skipstone_queue_new()) == NULL) {
+        goto error_queue_new_pending;
+    }
+
+    return service;
+
+error_queue_new_pending:
+    skipstone_map_destroy(service->endpoints);
+
+error_map_new_endpoints:
+    free(service);
+
+error_malloc_service:
+    return NULL;
 }
 
 int skipstone_message_service_register(skipstone_message_service *service,
diff --git a/src/message.c-e b/src/message.c-e
index f9754fc..8efb14f 100644
--- a/src/message.c-e
+++ b/src/message.c-e
@@ -19,7 +19,30 @@ struct _skipstone_message_service {
 };
 
 skipstone_message_service *skipstone_message_service_new() {
-    return (skipstone_message_service *)skipstone_map_new();
+    skipstone_message_service *service;
+
+    if ((service = malloc(sizeof(*service))) == NULL) {
+        goto error_malloc_service;
+    }
+
+    if ((service->endpoints = skipstone_map_new()) == NULL) {
+        goto error_map_new_endpoints;
+    }
+
+    if ((service->pending = skipstone_queue_new()) == NULL) {
+        goto error_queue_new_pending;
+    }
+
+    return service;
+
+error_queue_new_pending:
+    skipstone_map_destroy(service->endpoints);
+
+error_map_new_endpoints:
+    free(service);
+
+error_malloc_service:
+    return NULL;
 }
 
 int skipstone_message_service_register(skipstone_message_service *service,
diff --git a/src/queue.c b/src/queue.c
index 6c6e39a..8935a29 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -28,6 +28,18 @@ error_malloc_queue:
     return NULL;
 }
 
+void skipstone_queue_destroy(skipstone_queue *queue) {
+    while (queue->last) {
+        struct entry *entry = queue->last;
+
+        queue->last = entry->prev;
+
+        free(entry);
+    }
+
+    free(queue);
+}
+
 size_t skipstone_queue_count(skipstone_queue *queue) {
     return queue->count;
 }
@@ -41,10 +53,14 @@ int skipstone_queue_push(skipstone_queue *queue, void *value) {
 
     next->value = value;
     next->next  = NULL;
-    next->prev  = NULL;
+    next->prev  = queue->last;
 
-    queue->last->next = next;
-    queue->last       = next;
+    if (queue->last) {
+        next->prev = queue->last;
+        queue->last->next = next;
+    }
+
+    queue->last = next;
 
     return 0;
 
@@ -59,6 +75,8 @@ int skipstone_queue_pop(skipstone_queue *queue, void **value) {
         return 0;
     }
 
+    *value = last->value;
+
     queue->last = last->prev;
 
     free(last);
diff --git a/src/queue.c-e b/src/queue.c-e
index 6c6e39a..8935a29 100644
--- a/src/queue.c-e
+++ b/src/queue.c-e
@@ -28,6 +28,18 @@ error_malloc_queue:
     return NULL;
 }
 
+void skipstone_queue_destroy(skipstone_queue *queue) {
+    while (queue->last) {
+        struct entry *entry = queue->last;
+
+        queue->last = entry->prev;
+
+        free(entry);
+    }
+
+    free(queue);
+}
+
 size_t skipstone_queue_count(skipstone_queue *queue) {
     return queue->count;
 }
@@ -41,10 +53,14 @@ int skipstone_queue_push(skipstone_queue *queue, void *value) {
 
     next->value = value;
     next->next  = NULL;
-    next->prev  = NULL;
+    next->prev  = queue->last;
 
-    queue->last->next = next;
-    queue->last       = next;
+    if (queue->last) {
+        next->prev = queue->last;
+        queue->last->next = next;
+    }
+
+    queue->last = next;
 
     return 0;
 
@@ -59,6 +75,8 @@ int skipstone_queue_pop(skipstone_queue *queue, void **value) {
         return 0;
     }
 
+    *value = last->value;
+
     queue->last = last->prev;
 
     free(last);