[anigbrowl]

Yes, there's a grove connector for 3.3v on one end and more GPIO that can handle up to 5v. They have a lot of i/o on that particular device already allocated - there's a screen, a beeper, a microphone, IR and LED out, an RTC, and a 6-way motion detector, plus the buttons and a small (120mAh) battery with charging management hardware. If you are unhappy about having that much power and flexibility for under $20 you might be a little hard to please :-)

Larger units have 2, 3, or 6 grove connectors, plus a big library of pluggable peripherals.

[no_time]

My bad, I didn't notice the grove connector next to the usb port. I thought all you get is the few GPIO on the other side.