When it's someone's birthday in my office, we always pass around a card for everyone to sign and we decorate the birthday boy/girl's desk. I made this card for a male co-worker. It is the most masculine paper I have, so I have to make a trip to the craft store soon to get more options.
This is a simple card, and I used Pretty Pennants for the cut. I also love the paper on the matching envelope. I got inspiration from this great card.