Slit (?) & 'rectangular dock-like app'?

[William Leese]

two short questions, if someone could spare their time :)

i've seen the name "slit" appear every now and then, whats this?

Also, on some (most, actually) screenshots of BB at bb.themes.org i've seen a 
rectangular dock-like app containing various applets (clock, cdplayer, 
cpuload.. etc) once again, whats this?

thanks in advance,

William