Gilligan's Island to Hannah Montana

Meego (who was an alien) tried to contact his mother on the home planet by phone and instead the phone connected with Gilligan, Mary Ann and the Professor on Gillian's Island

Family Matters' Urkel appeared in the first two episodes of Meego.

The family from Step by Step was in the middle of a barbeque outside when Urkel from Family Matters came (literally) crashing in on the jetpack he had built on the last episode of Family Matters.

Boy Meets World and Step by Step both had episodes at Disney World and whiel in Disney World Eric from Boy Meets World met Dana from Step by Step.

Boy Meets World was continued decades later in Girl Meets World

Austin and Ally appear on an episode of Girl Meets World. Bringing the Disney Channel Live Action Universe into the Westphall Universe

The fictious show, America's Top Talent, is featured on Austin & Ally and Hanna Montana