Keep them in the fridge. Find other recipes that use celery. It’s quite versatile and keeps for quite a long time in the fridge! A lot of French recipes call for mirepoix (celery, carrots, onions; all diced) and Italian dishes call for soffritto which is the same thing. A ton of soups and pastas use mirepoix/soffritto as a base.

Now get out there and cook some celery, carrots, and onions!