My favorite recent ones:
1. getting lost on a crowded stage during a public event
2. stating that we'll send U.S. troops to Ukraine*
3. gagging on jalapeno laced pizza in front of the troops
4. stating that if Russia* uses chemical weapons in Ukraine then we'll respond in kind
5. stating that Putin* needs to be removed and that he's committing genocide and war crimes
*For the record, I in no way am in support of Russia or Putin, but these statements had to be "walked back" because they were "only Biden's personal opinions, not the official position of the U.S. government" or some such thing.