Some years back a company called SCO acquired some copyright to the Unix source code. Now that their close to bankrupt their suing every Linux distributer there is claiming their illegally using Unix source code in the Linux kernel. Apparently just about every major Linux distributer has been threaten with suing if they don't pay a fine.
People say SCO where planning this ever since they bought rights to parts of the Unix code but it turns out that they don't actually own the part of the code located in the Linux kernel. The people who do own this part of the code say that SCO have been desperate to get their hands on it but they have not been able too.