'Jersey Shore'-- Going Down Fast!

The male goombas of the "Jersey Shore" cast continued their integration back into the wilds of Seaside Heights by riding a roller coaster on the boardwalk this weekend ... perhaps the only instance anyone will be seen getting high this season.

Mother-to-be Snooki, thank God, did not partake in the ride ... choosing to soberly walk the streets with her fiancé/baby daddy instead.

As TMZ first reported, with Snooki pregnant and The Situation on the wagon ... the gang enjoyed their first night at a bar, but no one touched a drop of alcohol.