Renee Willis sends us a tip on filleting two parallel lines.
"Say you want to connect two parallel lines with an arc. Instead of going through the process of creating one from scratch, just use the Fillet command without a radius, and there you have it: an arc perfectly connecting your two parallel lines."
Notes from Cadalyst Tip Patrol: Set the fillet radius to zero, or hold the Shift key down while you use the Fillet command for a radius of zero. This is also a great way to trim two lines to their intersection point. It creates a zero-radius fillet. You can do that with the Chamfer command too, but it won't connect to parallel lines — too bad.