have never had my 360 freeze but what your describing sounds very much like a heat issue....had very similar issue on my pc when gfx card overheated due to faulty cooler....got temp down and everything was fine... try switching off the 360...check the vents arent blocked or full of dust...let it cool down...try again... good luck 
intel i7 3770k @4.4, ASRock Z77 Extreme 4, 16GB Corsiar Vengance 1600 ram, ATI 5850 BE, Antec 1 Case, Antec 1 550W PSU, emu0404, 120gb agility3 ssd OS, 2x60gbvertex2raid0 Games, 3 TB total sata2 Data. win7 x64.