[kirtakat]

[Your Area Code]-867-5309 is what I always use - alas they are becoming wise to that

[dylan604]

[areaCode]-555-1212 is one I use, but any 555 prefix will work as it is not meant for actual phone numbers.

https://en.wikipedia.org/wiki/555_(telephone_number)

[phyzome]

I've used 213-456-7890 a few times on throwaway things.

[867-5309]

cool example :)