I would put one portal on a pneumatically actuated plate above a dais that holds an object, and the other portal on a plate placed at a 45 degree angle. I would then see if an object on the dais would fly or fall out of the 45 degree portal, if the other portal actuated and closed the distance between its starting point and the dais.

Horrible things to greedy people all around the world.

Take a portal to a black hole, keep the portal open for funsies.

Nobody went with sending trump and musk to mars?

It would be a bad use of it, but probably pick a random road online and pick a random volcano. Whoever gets unlucky and doesn't notice the nightmare portal in the ground gets a free trip to the base of a volcano at no cost. Would obviously need the portal to be in a location where you cannot just easily return from, though. Gonna turn a random volcano and random street into quite the tourist attraction for no reason.

Portal to the edge of the universe?

Open a portal to the moon at the bottom of the ocean