I usually take a short five minute break every half hour to forty five minutes while I'm playing. It's a good time for a quick snack or to grab another beverage. 

How often do you take game breaks and what do you do?

Pause the WiiU and turn on the 3DS.

Just kidding. When I play, the only time take a break is it nature calls.

Eat, pee, feed / pet the cat, derp about on my phone maybe.

eating

I don't have breaks when I am playing only if I have to pee :D

Check the forum, browse the web a little bit, get a drink, stuff like that. I'm getting a sense of deja vu, didn't I just see this exact thread like an hour ago? o_O

I only game on the weekends so by that point, it's full blown leisure time.

I'll stop every two hours or so to smoke some recreational marijuana or a cigarette, make a drink or put something in the microwave

I sleep during my breaks, or work, most other tasks I can do during gaming