The music playing while Barney's parents are trapped in the elevator is a soul version of the groups mainstay "bang bang bangety bang," which was first introduced in 5x17.
Nancy Travis originally played Barney's step mom when he first met his dad (played by John Lithgow) however in this episode Nancy Lenehan plays his wife.
The Rastafarian hang glider eating a sandwich is yet another reference to showing sandwiches instead of marijuana.
The case that "Detective Mosby" couldn't crack was the reason for the pineapple in his room the morning after he forgets the events of night after drinking shots (S1E10).
Sherri Shepard and John Lithgow both star in Trial and Error (2017).