Here's a project that is not only quick and useful, but it's also a great last minute little gift. Once you learn the wedge repeat, it takes about 30 to 45 minutes from start to finish. It's also a great way to use up scraps of yarn since it only takes about 25-30 yards per coaster. It's also a great little project to stuff in you bag for knitting on the go.
The Tea Time Coaster pattern, which is designed for the CinDWood 1/2 inch gauge 10 peg thumb loom (pictured above), is available as a free Ravelry download. It could easily be made using 10 pegs on just about any loom but may require modifying the number of wedge repeats and/or the type of yarn used.