[p1esk]

start my new job the same day I give notice

This is bad advice. Most contracts in US explicitly prohibit this, so you could land in legal troubles if either company ever found out.

[dustintrex]

Most people in the US don't have contracts. Two weeks' notice is a convention, not law.

[froaway4job]

It's not advice. It's just what I do.

I've never had a contract that explicitly stated I couldn't work multiple jobs. (I work multiple full time jobs now)