Siesta! Siesta!
 

I didn't have much luck finding specific online info on siestas in Italy and Spain.

What time are the siestas in the big cities (Madrid & Rome) and smaller cities (Sevilla & Florence)? Any good suggestions on things to do during a siesta other than napping? Visiting museums, having a late lunch or snack, doing laundry...

offices and small family run businesses close for lunch from 1:30/2:00 pm. til 4:30/5. then they stay open to 7.30/8 pm.
all large stores and smaller ones bordering them stay open non-stop, as do most museums.

it would be the logical time to have a leisurely lunch before heading to next museum..
the menu of the day set price at lunchtime is an economical way to get a good meal.

In Rome a lot of things were closed between about noon (or 12:30) and 3:00 or 3:30. Churches, in particular where closed then. Some shops too. We got as early a start as possible and then ate during that time and generally sat in the shade. We also always had a "snack" (usually bread, cheese, and wine around 4:00 and then ate at 9:00.

Whatever you want to do during the "siesta" time keep one thing in mind..people do "siesta" because those are the hottest hours of the day :) So, as wilwl say..stay at the shade !!

Don't count on doing laundry in Spain during siesta. We tried that, trundling our laundry to the laundromat, only to find the laundromat closed for three hours during siesta. Also, most shops were closed during siesta in Spain, so it's not an ideal time to stroll and sight see, because corrugated metal grills sprayed with ugly grafitti covered shop whindows along streets that would have been fun and charming had they not been shuttered.

When in Spain, get in the same rhythm as the natives as quickly as you can - lunch and nap during siesta and stay up later than you normally would.

I didn't find Italy to be as locked down during siesta as was Spain.

I found Rome and Florence most the same as in Spain in the summer. Not the same in Northern Italy though.