Repair-a-Broken-Ethernet-Plug/
I just found this cute little how-to on repairing an Ethernet plug that has lost it’s catch:
Repair a Broken Ethernet Plug – More DIY How To Projects
http://www.instructables.com/id/Repair-a-Broken-Ethernet-Plug/
I’m not sure it’s all that practical for a $2-$5 cable, but if you’ve got a longer one or it runs under the floor or behind some bookcases, it might be worth a bit of time to fix it up.