I'm going this weekend to lima and completely forgot to make reservations. My plan is to hit the three restaurants in the "World's 50 best restaurants" which are (4) Central, (14) Astrid and Gaston and (44) Maido.
Central told me they were completely booked for dinner till the end of the year. I was able to get a lunch reservation this friday at 2pm. My flight lands at 12:30pm, so let's hope I make this.
Astrid and Gaston was easy to get a late dinner reservation on a Saturday at 930pm. I went there earlier this year and was able to get in on the same day I called, but it was at 10pm. We arrived earlier to see if we could get seated but we were told that we had to wait till 10pm.
Maido was fairly open on Sunday from 12 to 4pm.