We played elastics all the time growing up in Newfoundland. I am 36 now so I would have been playing mid 70s to 80s. I don't remember calling it anything other than skipping but it was more popular than the turn the rope games.

The rhymes we used were MISSISSIPPI with the actions as already described. We also used the verbal variant of M-I-crooked letter-crooked letter-I-crooked letter-crooked letter-I-humpback-humpback-I

B-I-N-G-O-BINGO was also popular - especially when you got to under-bums as it was considered an easy one. B-I-N-G were each done straddling alternate lines, O was in the middle and BINGO was both feet out.

Super-kala-freja-lipstick-expi-alla-do-chez (apologies to Mary Poppins for the spelling) was also popular. The actions were both feet in, both feet out, both feet in, one foot on each line- straddle one line, straddle the other, then both feet on one line and finally jump across with both feet on the other.

Finally, we also played a lot of triangle which was more popular when we got a bit older (you know - double digits and all). Triangle was played with a rope like elastics, but with three girls each holding a corner with one ankle (or a suitable inanimate object). Then the remaining girls would go through the sequence of moves until they messed up and had to take their place in the ropes. The sequence of moves was as follows: two feet - in/out around the triangle until back to the beginning; two feet - on the rope/in/on the rope/out/on the rope/in, etc until back to the start; one foot - in/out; one foot - in/on the rope/out. Sometimes we got fancy with backwards and eyes closed, but the first four moves were the basic sequence. Once you completed ankles, you moved on to knees and under-bums. The second time around you had to do each part twice before moving on...