Rock out to your favorite Summerfest performances for free this year when you give blood at an area BloodCenter of Wisconsin donation center.

The campaign is called "Give Blood, Go Free," and it's an effort to boost blood donations during the slow summer months. BloodCenter says between summer vacations and the decrease in school and community drives, it could use the extra donors.

"Blood donations through BloodCenter of Wisconsin are a priceless gift that can help save the lives of children and adults who are seriously injured, undergoing surgery or being treated for cancer and other illnesses," the organization said in a memo. "As a small 'thank you' to those generous donors, BloodCenter is offering a free ticket to Summerfest, which can be used at any time throughout the festival's run June 27-July 1 & July 3-8."