bleep!BOX is turning 3 today, and Genome MIDI Sequencer will be 1 next week! White Noise Audio has slashed the prices on both to celebrate! This is an excellent opportunity to get into Virtual MIDI. You can get both for $1 less than the retail price of Genome! Even if you don't use bleep!BOX as its intended acid factory, it is a highly customizable Virtual MIDI drum synth. Pair the two of these with just about any synth (link to tutorial on setting up several synths) and you've got the makings of an iPad studio.
To celebrate bleep!BOX's birthday, here is the original introduction by developer David Wallin, back in July 2009.