The only thing better than free ice cream? Two forms of free ice cream. Today, you can try complimentary milk shakes and scoops as two Harvard Square businesses duke it out to see who makes the best frozen sweet.

Ben and Jerry's ice cream truck will combat Harvey, b.good's whimsically named shake-making vehicle, during the event, which has been named the "Ice Cream Truck Battle." The contest will take place from 4 p.m. to 6 p.m. today on Dunster Street, the border zone between the two feuding sweet shops.

The event is sponsored by the Burger Brigade, a crew of students from Harvard and other local universities who plan to run the Boston Marathon dressed in burger and French fry costumes to raise money for the nonprofit organization Back On My Feet.

Today, both trucks will ask for donations to the charity, which promotes running as a means of empowering the homeless. The vehicle which takes in the most money will be named the ice cream truck champion. The real winner, of course, will be the charitable beneficiary—and you.