The Hammer Museum has free admission all summer. And it's air conditioned. Of course, the galleries are organized around a central courtyard, but last weekend, when the rest of the city was as scorching as it was today, that little courtyard felt like an oasis of shade and calm. Parking in the building costs $3 with the Hammer's validation, or there's a Metro Rapid stop right outside. They've also got some cool nighttime events......