My system has been crashing, and I think it may have something to do with Gnome since the crashes only occur when I'm using it. I checked the log file after a crash and it reported...
Gtk-CRITICAL **: gtk_accel_map_unlock_path: assertion `entry != NULL && entry->lock_count > 0' failed
so I went to the Ubuntu launchpad and searched for it, and here it is. Someone has already submitted a patch and the bug status has been changed to "fix released."
From reading the comments, I've learned the fix is only in Gnome 2.30, and Ubuntu 10.04 uses 2.28 (I think, maybe 2.26) (If it is possible to update to a new version of Gnome, please let me know). Luckily, someone also submitted a patch on the bug report as a temporary fix.
Unfortunately, I don't know how to apply the patch. I couldn't find much information regarding it online, and the only stuff I did find applied to using Gnome's git hub.