Don't let your fruits & vegetables go bad in the fridge! Check out this guide to learn proper produce storage
Some tips here:

TOMATOES STORING
Tomatoes should be stored at room temperature and then eaten within a few days once ripe. Hasten ripening by placing them in a paper bag with a banana or an apple. Never refrigerate tomatoes!

GRAPES STORING
Ripe grapes may be kept in a bag or shallow bowl in the refrigerator for more than a week. Freezing grapes makes for a refreshing snack on hot summer days. To freeze, simply wash and pat dry, then arrange individual grapes in a single layer on a cookie sheet or plate and freeze thoroughly (at least two hours). When frozen, transfer to a suitable freezer container.

Great tips here for all.. the complete list is here