Some 2,000 students from Berkeley and other universities crowded the space under Memorial Stadium last weekend to code and hack, night and day for 36 hours, in the second annual Cal Hacks hackathon. Packing pillows, snacks and laptops, they came together to create software and hardware projects — and to check out the many companies who set up booths, giving away promotional items and lending free hardware. Microsoft “technical evangelist” James Whittaker delivered the opening keynote. Berkeley News photographer Hanna Juehan Ye was there, with her camera; below are a selection of her images:

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