the biggest spider i ever saw was a banana spider at a lighthouse camp i went to when i was like 7. it had a huge web nest and looked to be about 7 inches long. nasty insect.
once i found tons of tiny little yellow and brown spotted spiders all over the walls and on the windowsill in my bathtub, maybe about 7 or 8 of them for several days. they were really small spiders though. i kept knocking down webs every day in this one corner and the next day i'd come in and bloop there it is again.
eventually my dad gave me this awesome pesticide spray, and i sprayed it all over the windowsills. it was supposed to kill all insects that enter the sprayed area for up to 6 months, and its worked great so far. never seen a single spider or its web again.