Sci-fi book about a boy who finds a portal to another dimension in his neighbor's playground set

Question

I'm looking for a book that came out when I was in middle school from 2010 - 2014.

I remember it being a humorous sci-fi book about a boy who finds a portal to another dimension in his neighbor's playground set, I want to say there was a tube slide that they went down. They visit another world (maybe future, maybe parallel?) and meet aliens. There is a part where they eat at a pizzeria.

The cover of the book is orange with a silver spaceship and all the characters on it. If I remember, the cover of the sequel to the book is lime green. There were some pictures in it as well, but not a lot.

Answer 1

Herbert's Wormhole by Peter Nelson and Rohitash Rao

Greetings. This story concerns a scientific anomaly that opens a portal, allowing us to traverse the space-time continuum and triggering an adventure that those of limited intelligence might simply describe as "awesome." Hey! This is a book about how we get sucked into this wormhole thingy and it drops us in the future where there's all this really cool futuristic stuff, but also these super-freaky aliens and we mess everything up and have to save the world. How awesome is that?

From this review

Alex wants to spend his summer playing video games, but his parents have other plans. They've built a (babyish) jungle gym and set up a play date with nerdy science kid, Herbert.

Herbert has spent his summer building a Negative Energy Densifier Suit. When the suits are worn by the boys on Alex's new jungle gym, they open a wormhole to the future. Only in this future, aliens called G'daliens have taken over. They all seem friendly enough, except for GOR-DON, who wants the boys destroyed. Now it's up to Alex and Herbert to save the future.

Found with search terms of site:goodreads.com boy neighbor slide portal (after many other variations, a surprising number of which brought up NSFW excerpts).