If you've ever had that one person who is impossible to buy for, take a moment and imagine trying to buy something for "The Big Bang Theory's" Sheldon Cooper. While you could buy him a collectible comic book or fun robot, the joy would wear off quickly. Remember how happy he was when Penny gave him Leonard Nimoy's napkin from The Cheesecake Factory? For Sheldon, it takes creativity to make him truly get into the Christmas spirit.
Give Him Control
The one thing Sheldon wants most on "The Big Bang Theory" is complete control. The best gift his friends could give him is a week of anything he wants. Let him be right about everything. Let him set the routine for the week. Take him wherever he wants to go. While it will drive them all crazy, a week of full Sheldon control is the ultimate gift. Just limit it to a week or two so it doesn't go completely to his head.
Dressing up for Game Night
Sheldon gets into the spirit of game night by dressing the part. As we all saw, he was completely happy dressing as a cowboy while everyone else went in plain clothes. The guys could participate and start dressing up as well. Everyone could be a different character or choose a theme.
Stop Stealing Internet
Sheldon regularly changes their wireless Internet password so people like Penny will quit using it. Penny could get her own Internet service provider and stop stealing from Sheldon. Of course, she could stop stealing food when the guys have regular food theme nights.
Follow the Rules
Leonard is constantly breaking the roommate agreement. Leonard could write up a new agreement that suits both of them and actually follow the rules. Better yet, he could follow Sheldon's rules without complaint.
The best gift for Sheldon is flattery. Compliment his ideas. Talk about how wonderful he is overall. While he already has an overinflated ego, it is the time of year for giving. Maybe his ego could actually get big enough to burst and then he'd be just like everyone else.
Sheldon, and even Amy Farrah Fowler, are always trying to understand the most basic of people skills. Perhaps Penny and Leonard could sit down with the genius Sheldon Cooper and teach him how to get along in society without driving anyone to the point of insanity or violence. This could take several Christmases, but the gang would enjoy seeing the transformation of Sheldon.