Speaking of t-shirts, Albany Area Math Circle will be putting in a new order for team t-shirts soon. These shirts are especially good to wear to travel competitions like HMMT and PUMaC, because they enable you and your team-mates to find one another easily in big crowds. And they also look spiffy in team photos celebrating various accomplishments.
For example, here are photos of math circle students celebrating the 3rd place team ranking in the A division in the statewide NYSML finals n New York City in 2007.
It's also a great idea for math circle members to wear their team t-shirts when they are working with younger students, as MATHCOUNTS student coaches or middle school math circle mentors.