I did some searching and couldn't find a post like this yet so if there is one I apologize for being redundant. and I'd be happy to delete this post.
I would like to start a list of veggies that make great pasta substitutions. I've done zucchini but that gets painfully old no matter how I dress it up. I'll start with a few I know of and if any of you know more options please post and I'll try to compile a main list.
Yellow or Summer Squash
I know what you mean about zucchini; I get tired of it so fast.
I like to use a combination of cucumber and carrot for a refreshing "pasta"--not too much like cooked pasta, but I'll take it over zucchini any day.
Beets are also fun if you don't mind your whole dish turning pink! Though I recommend mixing it with another veggie "pasta."
If you like seaweed, then thinly sliced kelp, wakame, or kombu can be marinated and used as a type of noodle--though there is definitely a strong seaweed taste.
And of course there are kelp noodles, which are a mixture of kelp and sodium alginate (a seaweed extract) that the manufacturer says is raw. I consider it an edible supplement (kelp is good for the thyroid and sodium alginate pulls heavy metals out of the body), and I seem to do perfectly fine eating it. It will get soft and pasta-like after 20-30 minutes sitting in sauce. And it's only 18 calories for a 12-ounce package.