Here are some ideas - although these are more oriented toward women, you can probably substitute some of your favorite "guy things"
Carole Brody Fleet: Single On February 14th?: 10 Ways To Enjoy Valentine's Day On Your Own
When I lived in CT, I was in the Sweet Adelines, and we spent the day delivering "Singing Valentines". It was fun, except for the couple where one did not want to get back together, and the "Stalker Valentine" someone ordered.
(A clever and creepy way to beat a restraining order!)