How would you invest $50,000?
dlg: Be careful: If you're in the US, to do most angel investing, you must be an accredited investor, per SEC regulations.  To qualify, you must have a net worth of at least $1M or have made >$200K in each of the last two years (>$300k if married).  Almost any company with a good lawyer will require that you sign something certifying that you are accredited.