I have a friend who enjoys ballroom dancing. She has been dancing for many years and continues to train. I do not know that much about it and would like some ideas of events she may injoy going to in the Los Angeles area. Any suggestions?

Your best bet would be to use google to find places...
this link seem to give some useful information.

http://www.ssmg.net/newpage31.htm

Most ballroom studios have open parties. Call a few near you and ask how big the floor is (the bigger the better), how many people come (the more the merrier, within reason), what kind of dances the dj will be playing music for (make sure it's the dances she enjoys--if she's a ballroom dancer, look for waltz, foxtrot, rumba, etc. and probably avoid dances that focus exclusively on swing dancing), and what level the dancers are (it sounds like she'll enjoy dancing with more advanced dancers). Have a good time!