[color=darkblue]I'm partial to a technique I found on a homebrew website: I "pool" my mooks into tight groups, like 5 mooks per group, and roll one attack for the group. I add +1 AV for every mook above the first, if they're attacking the same target.
This way, groups of mooks attacking one character actually have a chance of causing some harm (most Mook Groups attacking in this manner get +4 AV to hit!), but I only have to roll once.
Saves buttloads of time if there are, say, 20 unnamed goons attacking your PCs in a warehouse or something.
If I get down to only a few mooks fighting, I tend to just roll one positive die for each mook; since most unnamed can't hit an experienced PC unless they roll at least one positive 6, I don't need to bother rolling a negative die for each one unless that single positive die comes up a "6". (In other words, unless I roll an exploding 6 positive die, I never bother rolling a negative die for mook attacks.) It just makes for fewer dice hitting the table each Sequence.