I have to go with the ElAl Deal from 2012 for two reasons:
- First the deal itself, it enabled me to visit my brother in Yeshiva AND take my oldest for his first trip to E"Y
- Secondly, it was the way I originally discovered DD, and all of the other benefits I've derived over the years not just deals - but the fun discussions here on DDF. (Incidentally, because of the myriad of sign-up bonus posts that I've taken advantage of, I am now taking my second son to E"Y.)
I"H the 2020's will be just as great.