Here are some funny names I thought of, along with some real funny names from the books. There's also some funny nicknames at the bottom.

Made Up Names:
(Sorry if these are used in the books)

Brightlight
(Gremlins Movie)

Rabbitfoot
(He's lucky)

Chillpool
(Ice Cream)

Yellowtail
(Liquor, wine, sushi)

Whitestag
(the clothes brand)

Sunshades
(sunglasses)

Real Names:
(Sorry if there are any spoilers)

Firestar
(Superhero)

Talltail
(Tall Tales)

Sandstorm
(It's in the dictionary)

Yellowfang
(Bad Breath)

Foxheart
(She's mean)

Cherryfall
(Cigarette cherries fall, George Washington made the cherry tree fall by chopping it down)

Raincloud
(its a real word)

Redtail
(technology company)

Sunstar
(Orthodontic care)

Nicknames:

Dirtstripe
(Graystripe and Firestar about Darkstripe)

Berrystumptail
(Hazeltail and someone else I forgot about Berrynose)

Jaynoeyes
(Hazeltail and someone else about Jayfeather)

KittyClan
(Tigerstar or someone else about ThunderClan after Firestar takes over)

Hope a few of these made you laugh!

:-P