Grumble away. I don't mind the $20 even though I am spoiled by free museums here in Washington, but paying to go in the restaurant seems like a ripoff to me. Calling the ticket price voluntary when it isn't is pretty cheesy too.Speaking of eating at museums, here's a couple of restaurants I can recommend.1. The fancy restaurant at the Tate London (not to be confused with the Tate Modern) is super. Great wine list too. Not cheap. In fact, it is downright pricey but worth it-the place is a destination. If memory serves me right, there is also some cafeteria-snack bar thingie if you have kids in tow or just want coffee.2. In spring and summer when it is open, grabbing a salad and a bottle of wine out on the roof of the Uffizi in Florence can be wonderful. Great views of the Duomo and the salads are decent too. I was there last month and the terrace was somewhat restricted which didn't matter since it was way cold out anyway. The indoor restaurant is OK but you'd rather be outside if possible.3. The Louvre, as we all know has a great restaurant. The Picasso Museum in Paris has a lively outdoor cafe too.4. For sheer romance, if you go to Giverney, you used to be able to grab a nice salad and a bottle of rose' and sit in Monet's garden with rose petals raining down on you!5. If you make the day trip from Paris to Auvers-sur-Oise, you can visit Van Gogh's grave, Dr. Gachet's house, the sites of many paintings-even the room where Van Gogh died. The boarding house Van Gogh lived in remains as l'hommage. It just so happens that there is a dining room in the place, where you can enjoy a classic six hour lamb and a bottle of Costières de Nime! 6. Finally, when visiting DC's museums, the place to eat is the cafeteria in the sculpture garden between the Natural History Museum and the West Wing of the National Gallery. Nice soups and salads plus other stuff, you can get a drink, the music is always interesting and the scenery is hard to beat - you sit in a lovely garden with the National Archives looming over you. There's a wonderful fountain in summer and they turn it into an ice skating rink in winter. In the summer they have jazz concerts after work on Fridays. Skip dessert, though, and head over to the snack bar beneith the courtyard that separates the East and West Wings of the National Gallery. There you will find the best gelato this side of Italy.