fabric folding, making tiny quilts that are postcards (can be mailed), how to decide on patterns/designs for FMQ, and making quilted bags (like bowtucks). Making a needle holder or pincushion (where you actually make the item in the class) would be cool.
Timing on classes should be determined not by a preset slot but based on the content. Some are fast and others need much longer...
"make and take" where you can leave with a sample of something you've made would be a way to draw me in. Alot of samples/show and tell, demonstrations, hands on portions would be great. Most people don't sit still for too long.
I also get annoyed when people chat in the middle of a meeting or class.
Classes should be clearly labeled and defined by skill levels and content. Having beginners in an advanced class asking questions that do not benefit anyone else is irritating. Being a more advanced quilter and accidentally attending a class that is too easy/basic is also irritating.
Love it when the appropriate supplies are available to look at, try, and purchase so you can race home and try whatever you just learned. Not pushy sales, just available for purchase.