What should i engrave on my boyfriends zippo?

I got my boyfriend a Cowboys Zippo lighter. Its really nice by itself but i want to make it personal with an engravement. I dont want to make it really corny like you light my fire or hot stuff maybe i love you... I dunno hes just a manly guy who doesnt appreciate the romantic stuff, hes ur typical mans man. Any suggestions?|||romo sucks.|||how about just a date-ie-the date you got together --your birthdate-and your initials