Brethren Fast, Saturday, December 30, at Cricket on the Hill, is well named. The threesome is built on the guitar of Don Messina and bass-ic thumping by his brother Mik. Likewise, the tempos they utilize most often are quick, quicker and quickest. Sometimes the sound, like the instrumentalists' sideburns, recalls Fifties rockabilly, but more often the Brethren engage in straightahead R&R the way it was meant to be played: simply, and with plenty of verve. It's nothing new, but who needs new all the time?