Signs as Dad jokes they would say/use...Someone get me off the internet
Disclaimer: None of these dad jokes are mine

Aries:
What time did the man go to the dentist? Tooth hurt-y

Taurus:
What did the father buffalo say to to his son when he went off to college? Bi-son!

Gemini:
How do you make holy water? You boil the hell out of it!

Cancer:
Child: Hey I was thinking..
Dad: I thought I smelled something burning

Leo:
Child: DAD! I'M HUNGRY!
Dad: Hi Hungry, Im Dad

Virgo:
You heard of that band 1023MB? They're good but they haven't got a gig yet

Libra:
Child: Dad, make me a sandwhich
Dad: Poof, you're a sandwhich!

Scorpio:
I asked my dad for his best dad joke and he said, "you"

Sagittarius:
*Dad driving past a graveyard*
Dad: Did you know that's a popular cemetary? Yep, people are just dying to get in there

Capricorn:
When you ask a dad if he's alright : No, I'm half left

Aquarius:
How does Nasa Organize a party? They Planet  

Pisces:
Server: Sorry about your wait
Dad: Are you saying I'm fat?

Bonus:

Capricorn, Aquarius, Sagittarius, Scorpio:

Mom: How do I look?
Dad: With your eyes

Leo, Libra, Aquarius, Aries, Cancer:  (..I'd totally do that)