This gift is simple to make, personal, and practical - it pretty much has it all. Decorating a mug is as easy as talking some sharpies, drawing a design or writing a message on a ceramic mug, and then baking it in the oven. You can make the design however you like, so you can suit it to the person easily. For example, I made one for my friend that loves science, so I drew the chemical structure for caffeine. Be careful though, it's a bit tricky to draw on a curved surface! (Pro Tip: Alchohol can erase sharpie if you make a mistake.)
This is another fun, practical gift that is perfect if you have a sibling or friend in college that is coming home for the holidays. This idea consists of getting a container (perhaps a shower caddy or a laundry basket) and filling it up with college essentials. How you define "essential" is up to interpretations. You might consider filling it up with notebooks, pencils, and pens or maybe putting a lot of candy and top ramen.
This gift is perfect for a geeky or retro-minded friend. It involves drawing a grid on corkboard, cutting out a shape, then painting in the squares to create an authentic-looking pixel design. This can range from flowers, to stars, to iconic 8-bit symbols (this instruction video shows how to make hearts from the Legend of Zelda series). I have made this for myself and even though it took more time than anticipated, the result looked fantastic.