Cover round mini boxes with paper in the graduate's school color; top with a matching square envelope and tassel. Stash candy or a class ring in the box, and a big-ticket item (hello, crisp check) in the envelope.
At your post-commencement party, leave this themed box by the door. The guests can tuck their cards signed with best wishes and congratulations to the newly-minted graduate into the slot as they arrive.
School's out—forever! Throw a party with all the pomp and circumstance befitting their hard work with handmade invitations, decorations, guest books, and keepsake gifts before they embark out into the world.