* Irish--The Celtic band Altan will play jigs, reels and ballads tonight at UC Santa Barbara's Campbell Hall. The much-lauded quintet is from Ireland's northernmost county, Donegal. Show time: 8 p.m. $19-$25. 893-3535.
* Classical--St. Paul Chamber Orchestra, led by Bobby McFerrin, will perform tonight at Arlington Theatre, 1317 State St., Santa Barbara. Presented by the Community Arts Music Assn., the concert will feature works by Bizet and Vivaldi and solo improvisations by McFerrin. Show time: 8 p.m. $30-$65. 963-4408.
* Outdoors films--Best of the 25th annual Banff Mountain Film Festival will screen Friday at 7:30 p.m. at UC Santa Barbara's Campbell Hall. The popular screening features the top international films about mountain climbing, outdoor adventure, wildlife, the environment and mountain culture. This year's highlights include Swiss director Thomas Ulrich's humorous film "El Capitan," in which two Swiss climbers attempt the Mescalito route up El Capitan in Yosemite National Park. $12 general, $7 students. 893-3535.
* Theater--Theatre UCSB will open Neil LaBute's "Bash: Latterday Plays" Friday, featuring a trio of dark and incisive one-acts by the writer and director of "In the Company of Men" and others. Performances will be at UC Santa Barbara's Performing Arts Theatre. Show times: Friday-Sunday and Tuesday at 8 p.m., with 2 p.m. matinees Sunday and March 3. $16 general, $12 senior citizens and students. 893-3535.