LORELAI: How’d it finally end with Cheech & Chong?
Cheech & Chong, comedy duo consisting of Richard “Cheech” Marin (born 1946) and Thomas “Tommy” Chong (born 1938). They found commercial and cultural success in the 1970s and 1980s with their stand-up routines, studio recordings, and low-budget feature films, which were based on the hippie and free love era, and especially drug and counterculture movements, most notably their love for cannabis.
Their 1978 buddy stoner comedy film Up in Smoke was poorly reviewed but a huge commercial success, becoming a cult classic and kicking off the entire genre of stoner movies. Their characters are a pair of drug-addled idiots who get into one ridiculous slapstick situation after another, so Lorelai seems to be saying that Jess and Dean are likewise a pair of comedic idiots.
The real Cheech & Chong broke up in the 1980s after an acrimonious falling out and didn’t reunite until 2008 – Lorelai may also be referring to that (not that she knows Cheech & Chong will get back together at this point).
The Annotated Gilmore Girls 