that and the wacky drum sounds.. mostly snares... and 909 doesn't play the main role all that time, ... program a lot of drums with out any timming reference (i.e. metronome or kick), then add the kick exactly contrary 2 where u would expect it 2 be (generally this means (3/16, 7/16, 11/16, 15/16)....
Also lots'a shuffle and a snare on 4/16, 8/16, 12/16, 16/16).. then go creative on these snares!!

Also compression.... kick comes in and brings all the perc. down!!

Z