Since I'm not a pro user, I can't make a gift guide, but I'm sneaky enough to still make a guide to gifts for guys! Hope you enjoy, if you have recommendations post them in the comments and I just might add them ;)
First up, We have 3-D cookies ! http://www.instructables.com/id/3D-Cookies/ The image won't be totally "3-D" but it should stand out from the background when you wear the glasses! I can see these being awesome for any aged guy or girl!
Second, learn to make a knife out of a nail. They are quite small-seems like they'd be perfect for cutting small cheeses or mounted on the wall or even made into a necklace. http://www.instructables.com/id/KNIFE-FROM-A-NAIL/
Third: This is an Instructable for DIY Scratch-off business cards, but it could be adapted in many ways! :) Scratch off surprise cards for the boyfriend maybe? http://www.instructables.com/id/DIY-Scratch-Off-Business-Cards/
Fourth: Viking shoes! I have actually made myself a pair of these, and they are super comfy, especially because they are molded on your own foot shape. Depending on the guy you're making them for, they could be the perfect, simple Christmas gift. http://www.instructables.com/id/Viking-shoes/
Fifth: For the guy who has everything...
Grow a gourd for him. That's in the shape of HIS FACE. yeah.
Sixth: Chocolate is always a good way to go, in my opinion. This is another Instructable that I can totally stand behind-tried it several times and it always works perfectly! Takes a little time, but oh so worth it. http://www.instructables.com/id/Anatomy-of-a-Chocolate-Truffle/ My most popular flavor was Guiness. I just added a couple of tablespoons of dark beer in place of some of the cream, they were a total hit with both the boyfriend and the dad!
Seventh: For a certain kind of guy, this could be the perfect gift. Plus, they're pretty rad. http://www.instructables.com/id/Luminous-Mushroom-Night-Light/ Luminous Mushroom Night Lights!
Eighth: Bowl of Worms! Depending on the guy and the age, these could be a hit. I'm a 19 year old girl and I would love these, but then again I'm not totally normal. ;) Also, some suggestions in the comments tell how to make the worms "adult" by replacing some water with vodka. Embrace your inner child. http://www.instructables.com/id/Bowl-of-Worms-Anyone/
Ninth: Dinosaur Excavation Cake. I want this for my 20th birthday. I want it. Therefore, I have decreed that many other people must love it as well. From your little brother to your boyfriend to maybe even your dad, play with your food! http://www.instructables.com/id/dinosaur-excavation-cake/