I want to start entering magic competitions as often as I can. Anyone know where or how to find out when/where they are and how to enter? Magic Castle has the Strolling Showdown, and I think IBM rings host competitions as well right? Any ideas?

Preferably in SoCal haha.

Actually, you are more likely to find contest opportunities at regional conventions hosted by local clubs. Here's the contest information page for the P.C.A.M. Convention (PACIFIC COAST ASSOCIATION OF MAGICIANS):
http://pcammagic.com/contests/

Be sure to check the contest rules
http://pcammagic.com/general-contest-rules/

----- Amado "Sonny" Narvaez