When telling Michael about his prison shower escapades, Barry (laments that he has the worst (bleeping) clients, mirroring George Sr. (indirectly) referring to Barry in Pilot (2003).
GOB mentions the possibility of kids having thrown the banana stand in the water, which was brought up for the first time in Afternoon Delight (2004).
The banana suit, first seen in Afternoon Delight (2004) makes another appearance (this time worn by Tobias).
Portia de Rossi quit acting in the middle of 2017, but Mitchell Hurwitz convinced her to work on a story line for Lindsay, and she loves the show so much that agreed to be on 5 episodes of season 5.
The tradition of Bluth family members giving lessons (or trying to) is directly mentioned several times during the episode.