Amazing for portability are the Insta-theater screens by da-lite.  Place the whole case on the ground, and then pull upward.  Presto!  you are ready to go!

We recommend the inst-theater-Plus, or the Insta-theater delux.  both are great for portability.  The delux version has a double scissors structure, and is very durable - but is a bit heavier than the Insta-Theater Plus