Mawaru Made In Wario Hints
A complete list of numbers that can be dialled on the black phone in Mawaru Made In Wario was published in the 20th November issue of Famitsu. You can find the phone (if you've gotten it from the toy machine that appears when you beat a boss) in the "Other" section of the toys list, marked by a "?" icon.
0099 0222 0881 0883
1111 1153 1203 1212 1234
2525 2569 3999
4111 4122 4123 4141 4182 4906 4949
7171 7456 7946
8324 8472 8888
In case you're thinking that they had some poor lackey slaving over a GameBoy Advance, dialling a thousand numbers and noting which ones worked... it seems that the toy machine will occasionally give you a phone number to ring. But they aren't stored in the toy section, so you have to make a note of them.
Of course, when you ring the number it shows what the person on the other end is saying. In Japanese. One of them is the weather forecast, so it starts raining out of the earpiece on the phone. Another has someone reciting the first few characters in the Japanese syllabary while laughing.