Do you need an Aperture Science Handheld Portal Device? Of course you do!
Sure, there’s a life-sized replica out there in the world, but for those of us with smaller living rooms (and smaller budgets), this miniature edition, from ThinkGeek, is just the ticket.
https://kotaku.com/buy-your-own-life-size-portal-gun-5883592
This model, admittedly, can’t actually make a wormhole in your wall. But it does come with the lights and sounds you need to feel like it actually works.
You could even put a potato on those arms. A baby potato, admittedly, but still.
Portal 2 Miniature Replica Portal Gun [ThinkGeek, via Twitter]