JESS: Potlucks and Tupperware parties aren’t really my thing.
A potluck is American English for a communal meal where everyone brings a dish of food to share. Commonly organised by churches and community groups, the food is rarely of gourmet quality (hence, you’re taking “pot luck” in what you’ll get to eat).
A Tupperware party is one organised to sell Tupperware, a line of plastic storage containers first developed by Earl Silas Tupper in 1946, and sold via multilevel marketing in the home. After being very popular in the 1970s, Tupperware suffered a slump in the mid-1990s, when it began to seem dated, so at this period was considered a rather middle-aged activity.
Quite rudely, Jess equates the lavish dinner Sookie carefully prepared to welcome him to Stars Hollow with community meals suitable for the dull and old-fashioned. This yet another meal prepared by Sookie which gets ruined, as Jess and Luke leave without eating, when the dinner was meant to be for them.