Learn Turkish: Parti büyük ve eğlenceli.

Yes! In this sentence, ve connects two descriptive words (büyük and eğlenceli) just like "and" connects "big" and "fun" in English. When listing adjectives like this, you can just drop it right in the middle.

Where is the word for "is" in this sentence?

There isn't one! In Turkish, when you want to say "it is", "he is", or "she is", the "to be" verb is usually invisible. Just putting the subject (Parti) and the adjectives (büyük ve eğlenceli) next to each other is enough to mean "The party is big and fun."

Does the -li at the end of eğlenceli mean something specific?

Yes, it does. The suffix -li (which changes to -lı, -lu, or -lü depending on vowel harmony) means "with" or "containing". The base word is eğlence, which means "entertainment" or "fun". Adding -li makes it eğlenceli (literally "with fun"), which we use as the adjective "entertaining" or "fun".

Is parti just the English word "party"?

It is a borrowed word, but like many Western words in Turkish, it actually came from French (partie). It sounds just like the English word and means the exact same thing, making it very easy to remember!