Here are any phone tricks I have found. Use them at your own risk! <phone number> means that's where you insert their phone number.
*67<phone number>*
Block Caller ID
*69*
Redial the person who *67'ed you (Last Call Return)
(Not many people know about it)
*57
Verizon Unlawful Call Center (Costs $1 to use) (Malicious Caller Identification)
*77 (on) *87 (off)
Anonymous Call Rejection (blocks anonymous calls)
(408)-236-2060*
Rejection Hotline
More phone numbers can be found at RejectionHotline.com
911-<any four numbers>*
Calls 911 immediately when you type it in
*Has been tested. (Do not actually type the star in.)