I also needed to make some masculine birthday cards for my parent's store, but I struggle with these a bit...as I'm not used to doing "masculine" anything...and I like pink and bright colors, so it was a bit of a challenge. My favorite one ended up being one I "card-lifted" from fellow Craft Warehouse Design Team member, Amanda Sherman. I was on her blog and saw this design (hers was a Father's Day card), and really liked it...so I adapted it a bit...and this is what I came up with.
Paper by My Mind's Eye
Buttons from Lasting Impressions
Stamp from Paper Trey Ink