In general, you can discuss such ideas but agreeing to perform them brings you up against the line of committing crime. In the US, you have to commit some material act in furtherance of the conspiracy, but that can be almost anything.
For example, if you and your friends agree to rob a bank and decide you'll need gloves, ski masks, and some kind of weapon, buying 6 pairs of rubber gloves at the store the next day would qualify as a material act. You don't need to acquire all the expected tools or go anywhere near the bank you discussed robbing.
For example, if you and your friends agree to rob a bank and decide you'll need gloves, ski masks, and some kind of weapon, buying 6 pairs of rubber gloves at the store the next day would qualify as a material act. You don't need to acquire all the expected tools or go anywhere near the bank you discussed robbing.