Alright, I've been on a rampage lately. I had previous built all three Sloths, a DelayNoMore, a Neuron, and a 1050 Mix Sequencer.
I recently finished a BOOLs, a Giant B0N0, a Brain Custard, an 8-Bit Cipher, and a Sloths (the new 8HP triple Sloth with 11 outputs and CV control). I'm currently wrapping up Chopper, FlipFlopChaos, Feague, a double Neuron, and a Squid Axon.
Sloths (8 HP triple Sloth): This is it. This is the one. Build this. This module has excellent taste. Having 11 outputs and CV "control" makes it a new hub for slow, generative patches.
DelayNoMore: One of my favorite effects in Euro. I'm not using this in the full-tilt NLC video way. Instead, I love using it as a gritty, low-fi delay with a ton of hiss. If you like the PT2399 sound, this is definitely worth checking out.
1050 Mix Sequencer: Super flexible design based on an old ARP module. It can function as an 8-step sequencer, two 4-step sequencers, and eight channel mixer, two 4-channel mixers, an 8-input to 1 output switch, two 4-to-1 switches, etc. There are also Diff-Rect outputs to smash the two halves together. I believe that this would be insanely popular if it were manufactured by a larger company.
BOOLs: Very cool, but I'm currently selling it. This is a great module if you don't have interesting logic duties already taken care of (I have a Plog, which is more logic than one typically needs). The most interesting feature is that it produces a stepped and slewed voltage pair that are based on the state of the four logic outputs. I ported this over to Reaktor since it was straightforward, fun, and useful.
Giant B0N0 & Brain Custard (audio rate version): Crazy, but not for me. I sold these pretty quickly, as I knew that they weren't going to fit in to my patching style. The video demos of these are very accurate. They're both very violent and unpredictable. B0N0 has a lot more versatility, as it has a chaotic CV out, two oscillators, a delay, and two gates (one audio rate, one slower). I may try building the Brain Custard CV version, but I think I'll be satisfied with the Sloths.
8 Bit Cipher: This is like a plus-size Turing Machine. It has the same 8-bit shift register concept, but there are two Data inputs (kind of like having voltage control over the write-1/0 switch on the TM). If Data2 is unused, bits 1 and 8 are XORd and normalled to that input. It creates really nice, complex patterns. All 8 bits are available as gate outputs (kind of like the Pulses expander). There are 4 CV outputs that are voltage variations of the contents of the shift register.
Neuron/Diff-Rect: The single Neuron is a simple circuit that ends up being a lot of fun. There's a 3-input unity mixer that feeds a comparator. If the mix exceeds the SENSE parameter, a square wave of an amplitude set by RESPONSE is added to the signal. This sounds great as a waveshaper, but I enjoy it primarily for adding some nice discontinuities to CVs. The Diff-Rect is a interesting sub-circuit that outputs the rectified sum and difference of two input pairs. I enjoyed this module enough that I am now building a dual Neuron.