If it was self-employment (SE) income, then you need to report it on a Schedule C, and pay SE tax on it (if it was more than $400.).
If it was money from gaming or for anything else that you don't owe SE tax on, report it on line 21 of Form 1040.
To report it on line 21, go to Miscellaneous Income>Other income not already reported on a Form W-2 or Form 1099.