An electrical outlet is hot to the touch but nothing is plugged into it

A receptacle that is hot with nothing plugged in is a sign of wiring failure. This may cause a fire at any time. PLEASE turn off the circuit breaker to this receptacle immediately and call a qualified electrician to correct the problem. Do not do this yourself, even if you have some qualifications, there are major problems you will likely miss.

99.9% of the time this is just going to be a loose connection at the receptacle. I bet you are also =having problems down stream (flickering lights etc). An AM radio is probably painful to listen to.
Mr Brown is right. Get this checked out before you have worse problems.

Do you have aluminum wire?

Willijmon:

As your profile does not indicate you are in the electrical trade....

Please contact a licensed professional in you area to check your 'hot' receptacle promptly.

I am locking this thread, as providing 'advice' to DIY people is non-approved.