A couple of products that have been out of stock in the phenoptix store for a while are the Ice Tube Clock and Conway's Game of Life.
Both are awesome blinkly kits. The Ice Tube Clock is a super cool (hence ice) nixie tube (hence tube) chronometer (hence clock). It's a bit of an advanced kit due to the number of components and the consequences if you don't follow the instructions properly. To drive the nixie you use very high voltage so the chances of a jolt are also higher than with most projects. All that said I was able solder one up without issue (mostly down to the excellent tutorial provided by Adafruit). I took my time and took about 100 pictures to make this gif.
The second kit is the Conway's Game of Life, this is a nice easy Sunday solder. It makes a satisfying piece that automatically plays the Game of Life, where LEDs live or die depending on a formula preset in the ATMega.
Both are excellent kits well worth a bit of time with your soldering iron and they're both back in stock in the UK.