Hi,
Make arrangements for one or two team members to be responsible for purchasing birthday cards and having coworkers to sign them.
If your budget and circumstances allow it, consider giving a "lunch-sized" restaurant gift certificate or having a small party. And if you're really enthusiastic, go ahead and add some birthday decorations to the birthday person's office or work area.
Everyone likes to feel special and zeroing in on birthdays is an easy way to do that -- with the extra boost that such attention is likely to create for employee morale.
Fayeg