Looking for genuine Mammoth Chunks (TM)? Some genuine Anti-RobotFluid, or 100% Non-Organic Robot Milk? Maybe some Barbarian Repellent for a weekend trip back to whenever?
Then you need the Echo Park Time Travel Mart (motto: "Wherever You Are, We're Already Then.")
If you can't make the time to visit them... well, then you're really not one of their customers, I guess. But you can still browse through a photo journal of their inventory, or watch the video walkthrough of the store.
Keep in mind, though, that the Hyper Slushie machine is out of order - come back yesterday.
What makes this even cooler, at least to me, is that this is apparently the work of 826LA, a non-profit tutoring center. The Time Travel Mart is a front for the new writing lab they are building in Echo Park, CA. They're an educational institution with a sense of humor. That's only slightly less amazing than a real time traveler.