MBM does have an option to place the temps in a corner of your screen, but it won't work with gaming. You'll get extremely heavy glitches from the temp trying to superimpose itself on the screen and the game not wanting to let it.
It's easier to just play the game ( or run FAH, which gives you a constant load temp, not a temp that your cpu spiked to... b/c MBM will give you the highest temp that it recorded, which probably won't be your stable load temp). I would suggest FAH and then just look at what your temp is in the toolbar.