''Haggadah (or the Passover Show),'' Witness Relocation's new production at La MaMa E.T.C., stands as a noisy rebuke to that too-familiar creature: the interminable family Seder. A whirl of speedy activity, with projections, music, dancing and short skits, ''Haggadah,'' directed and choreographed by the troupe's leader, Dan Safer, is theater for the short-attention-span, when-do-we-eat? crowd. Conceived collaboratively -- the program calls the eight performers co-creators and co-choreographers -- the show is more a series of riffs than a retelling of the Passover story, in which Moses leads the Jews out of captivity in Egypt. There's a hit-or-miss quality to those riffs, which run from silly (Moses, encouraged to have a jelly bean, opens a can and a paper snake pops out) to sober (a Holocaust-like story about a hut full of dead bodies). [ABSTRACT FROM PUBLISHER]