If I were you, I would regift it and send it to the "houdinii" character that posts messages on here every once in awhile.

Otherwise, I guess you could pot it and let it grow...then transplant into the ground in the fall.

Or you could try planting outside directly, but it might struggle.

Is it just a tuber, or is it a whole plant with stems and leaflets attached? Plant it now and it should get established before the winter. They have a tendency to go dormant as the season progresses, often loosing all leaves and stems in the fall. It should grow again next spring, and if it is old enough, it should flower too.