"We're environmentally sound; all of today's jokes are recycled from last week's show." [from Episode 82]
All S1
"Reproductions of the accounts and descriptions of this cartoon show is prohibited." [from Episode 83]
"And make sure you stick around after the show for the big cast party." [from Episode 84]
"If you could only watch one TV show this year, this is the one to watch." [from Episode 85]
"Hey, you could watch some other show, but why would you want to?" [from Episode 86]
"And don't let your dog watch this show. It's too good for him." [from Episode 87]
"Today's show is brought to you in color unless the artists ran out of crayons." [from Episode 88]
"You'll like today's show, folks. No Binky, no Nermal, no Buddy Bears - just a lot of me." [from Episode 89]
"Today's show is inspected for your safety by number 29." [from Episodes 90 and 95]
"Don't bother checking NBC, kids. They're not running cartoons anymore." [from Episode 91, although replaced with the quote above it]
"Everything else you watch on TV this week will just be anti-climatic." [from Episodes 91 and 94]
"If a tree falls while our sound effects man is at lunch, does it make a sound?" [from Episodes 92 and 93]
"Penelope's back today, folks. Some women just can't get enough of me." [from Episodes 96 and 97]
"Critics agree - of all the TV shows on today, this is probably one of them." [from Episodes 98 and 99]
"Think of a number between 1 and 10. The number you're thinking of is 7." [from Episodes 100 and 101]
These quotes come from Wikiquote's Garfield and Friends pages and are available under the Creative Commons Attribution-ShareAlike License.