(Temporary Ohel) Putting up a curtain between men and women. Making a wall of a Sukkah;
מחמת חסרון כיס Machmas Chesron Kis: The Strings of Unmade ציצית (Tzitzit);
more examples of "מבטל כלי מהיכנו" (nullifying a vessel from its normal usage) that come up on Shabbos;