Here's a way to make an XOR gate

This turorial comes with ASCII representations of the build process

First, create a donut of any common block (Wool is best to look like a real redstoneer). Use 8 blocks

■■■ ■□■ ■■■

Place a redstone torch marked where ○ is marked

■○■ ■□■ ○■○

Place redstone inside the little loop, then place redstone as indicated with a ●

●○● ■●■ ○●○

Place a repeater on top of each block represented with a ■ in the diagram just above

Place redstone torches on the side of the blocks as represented below

○ ○ .|...... | .v......v. ●○● ■●■ ○●○

Now place some redstone between the two new torches you just placed

○●○ ●○● ■●■ ○●○

Now you can place a lever on the two blocks on the bottom that hold torches

Combine with a T-Flop to make it usable with buttons