Found and poked around a big weird exhibition complex that seemed a little decrepit, but with some recent contemporary additions. Didn't go in, because the next exhibition to be shown wasn't open yet. Tracked down a cafe, had some lunch, and headed west through Letenské sady, a park full of weird surprises.
For example: some weird horsey-shaped play structures for kids, a giant (10s of meters high, surely) statue of a (working!) metronome that went kchnk kchnk kchnk in a delightfully horrifying mechanical way, big concrete plazas, great views of the city across the Vltava, little nature-grotto things, Schenley-park-esque ravines, a greenhouse labelled "Orangerie", some other miscellaneous monastic-looking gardens, doors set in walls several feet above ground. Tried walking uphill to our intended dinner spot, Maly Buddha, but the castle district seemed to be shutting down around 6pm, so the most direct walking path was unavailable. We were forced to go downhill instead bascially all the way back to the river --- at which point we finally gave up and figured out how to use local public transportation.
A number 22 tram got us to Maly Buddha, I ordered a fried rice with chicken making real sure to order it with No Nuts, and they were like Correct No Nuts in english even, and yet I got it and it had like one or two stray cashews on it and I was like... nope nope how about just nope don't want last day of nice vacation to be in the hospital. K finished up her vietnamese salad and I instead had another street sausage down near Karlov Most ("Prague Times Square", in the sense that it is the most tourist packed place that you'd just as soon never go, but which always seems to be in between point A and point B that you do want to go to) which was just fine.
Back in hotel now. On a plane back to new york tomorrow; still trying to decide if I want to visit pittsburgh for a brief not-even-vacation-visit-because-I-can-wo