I finished soldering together the Nuts & Volts PICmas tree kit last night. With an assortment of animated patterns, it makes a really nice holiday decoration.
The brains of the board is a PIC microcontroller (suprise!) which can be programmed with new patterns. It's a pretty simple through-hole soldering build. My only complaint us that LED solder pads could be bigger although in the end everything worked perfectly on the first try. I do like that it can be powered by either two D cells or a USB cable. The PIC uses PWM to fade the LEDs to nice effect and, at full duty cycle, they are nice & bright.
If you're looking for a fun DIY holiday decoration, then check out the kit's site for the design details and link to order page (full kit $40, just PCB & PIC $20):
I made one previously 2 years ago and gave to my grandparents who loved it.