Building a Bleep Labs Thingamakit

Dr Bleep was kind enough to send me a Thingamakit - his build-it-yourself light cell powered noise synth (it's the big brother of the Thingamagoop). The box arrived a couple of months ago and sat in the corner, mocking me. Fear of soldering is a terrible thing, and easily cured by a pair of Velleman crawling micro bugs - £10 from Maplin, 1 hour each to solder together, two happy kids, two parents with soldering fume headaches. So far, the Thingamakit is a joy (being assembled next to an open window and a desk fan). Every component is labelled, the manual is clear and helpful, with useful things like a big colour photo of how the populated board should look. The circuit board is was white until I gunked it with solder flux. Best of all, it worked first time. The kit comes complete with an unfinished 1790NS case and a drilling guide, but perhaps something more interesting will turn up.
Anyway, what should I build next?