Just sharing this little collection I have of some neat errors.
1959 - J100 $1 Rotary Press
1973 Commemoratives - 8 cent Rise of the Spirit of Independence - Drummer
1973-74 Regular Issue Coils Perforated Vertically - 10 cent Jefferson Memorial
1966 - 2c Frank Lloyd Wright
1964 - 5c Fine Arts - This error actually suits the stamp, being abstract and all....
1973-74 Regular Issues - 10 cent Crossed Flags