Quick Vietnam visit to attend an event

Hi I have an opoortunity for a quick vietnam visit for 3-4 days for an event scheduled in Ho chi Minh city.

Wanted to take advice of folks here of places I could cover in my quick visit.

1 day would go into the event and besides that I would have around 2.5 days( coz I have an evening flight on the last day).

What all I could cover in Ho chi Minh city/ around it for travel and stuff? Anything important to buy from around? / Souvenirs stuff? (The trip is in the last week of Nov/this month)