While showing admirable recycling motivation, sticking a clock inside an old coffee can isn't enough to impress us; Instructables member florinc makes the grade because his DIY IllyClock adds in some color magic too. Based on a Wiseduino - an Arduino clone with an integrated real-time clock - and an LED shield, the clock lights up its numerals in different shades depending on the time of day.
Video demo after the cut
Three hours before the alarm is set to go off, the numerals change from green to orange. Then, an hour before it's due, they switch to red. The idea is that you can squint at the alarm clock in the night and tell roughly how much time you have left in bed without actually needing to decipher the actual time.
If you're short-sighted then that could be a particularly handy feature. The Instructable is seemingly based on this previous IllyClock, as shown in the video below.