If bug algorithms are what i think they are, i haven't seen any used this year, but last year KRUNCH Team 79 had an awesome avoidance program. To the best of my knowledge it involved 3 sonars and possibly some other stuff.
below are two examples I could find, it was always fun to watch
http://www.thebluealliance.net/tbatv/match/2008fl_qf4m1
http://www.thebluealliance.net/tbatv/match/2008fl_sf2m1