Valentine's Day is a celebration of love, but no one says you can't have fun with it. If you have a fun relationship with a man who has a good sense of humor, try giving him a funny Valentine's Day present. You can always slip a funny gift in with the more sincere present.
Novelty clothing accessories are always a big hit when it comes to funny gift giving. T-shirts are usually the first piece of apparel to come to mind, and there are many humorous shirts to choose from both online and in traditional stores. RedEnvelope has a series of t-shirts with slogans like "Official Dog Walker" and "Weekend Chef." Boxer shorts with clever sayings are also popular. You can get a bit risque with a pair of men's thong underwear if you really want to push the envelope.
A novelty or gag gift is a standard humorous gift that offers a lot of options since there are so many to choose from and most are relatively inexpensive. If you can't find a good novelty shop in your area, do a bit of searching online through trusted retailers. RedEnvelope carries a novelty beer glass called the Hopside down Beer Glass. It looks like the top half of a beer bottle, turned upside down, is somehow magically inside the glass.
Scavenger hunts are both fun and funny. Arrange for your boyfriend to collect clues and go on a hunt for little presents or notes along the way. The trail can lead to his main Valentine's Day gift. The clues can include trivia relating to your relationship (just be sure not to make them too hard) and can include inside jokes. You can lead him around the house or get really creative and send him all over town.