Can you secretly record conversations between you and a friend?

Not without breaking the Michigan wiretap law.

No, party must consent.

California Penal Code Section 632(a) prohibits recording without consent. 632. (a) Every person who, intentionally and without the consent of all parties to a confidential communication, by means of any electronic amplifying or recording device, eavesdrops upon or records the confidential communication, whether the communication is carried on among the parties in the presence of one another or by means of a telegraph, telephone, or other device, except a radio, shall be punished by a fine not exceeding two thousand five hundred dollars ($2,500), or imprisonment in the county jail not exceeding one year, or in the state prison, or by both that fine and imprisonment. If the person has previously been convicted of a violation of this section or Section 631, 632.5, 632.6, 632.7, or 636, the person shall be punished by a fine not exceeding ten thousand dollars ($10,000), by imprisonment in the county jail not exceeding one year, or in the state prison, or by both that fine and imprisonment. However, California Penal Code Section 633.5 sets forth an exception if the recording is to obtain evidence of a crime. 633.5 California Code - Section 633.5Nothing in Section 631, 632, 632.5, 632.6, or 632.7 prohibits one party to a confidential communication from recording the communication for the purpose of obtaining evidence reasonably believed to relate to the commission by another party to the communication of the crime of extortion, kidnapping, bribery, any felony involving violence against the person, or a violation of Section 653m. Nothing in Section 631, 632, 632.5, 632.6, or 632.7 renders any evidence so obtained inadmissible in a prosecution for extortion, kidnapping, bribery, any felony involving violence against the person, a violation of Section 653m, or any crime in connection therewith.

In Michigan, you can record a call for which you are a "first party" participant (for example, you could not record a conversation that was between your husband and his alleged mistress). However, if the caller on the other end of the phone line is in another State or Country, that State's or Country's laws may apply, so please proceed cautiously.