Gina has some fabulous ideas that would definitely appeal to a man - great job!
Adding to that, try to think of all the work your husband has done as a 'SAHD' during the time when you needed to go to class, work on projects, study for tests, etc. I know a lot of SAHMs would just absolutely die for some 'me time' or a really cool girls' night out. I would recommend you give him the gift of some really cool free time with his friends to have the guy time he may have sacrificed (so graciously!) so you could follow your dream.
Does he like a certain band, is there a concert he might like to go see? Get him great tickets for he and his friends and perhaps order a limo.
A sporting event with the guys is also a fantastic idea. Would you be able to do a rooftop event at the Cubs game or a box/suite at the Sox game? If that's too big budget, then get a pair or a quad of great seats at a game for him and his buddies.
I don't know how your husband is, but you could also try the 'dress in lingerie' and 'give of yourself' gift to him. Buy something new and provocative and take care of his each and every need first! You'd be surprised at how many men would think that would be the best gift ever!
Good luck and it's so sweet of you to recognize your man in this way.