What can I invest in?

My husband wants to invest in a condo at Timberridge Lodge in Lake Geneva (if anyone is familiar with it). I think it's not in the cards for us to invest in something like that. It would take alot of our time and not to mention constant worry from me to make the 2nd mortgage payment and property taxes, and hoping that the condo will rent out for most days of the week/month, etc etc. I handle the budget and if we can't live within our means now, I just think that investing in real estate is just risky for us. What are some other things we can invest in? We already invest in the stock market and we both have 401k at work. I told him if he wants investment advice to call my dad, and he got mad at me. What I wanted to tell him was that my dad is retired and living in a nice house in Florida, but his mom and dad are still working in their middle 60's. I think my dad has it figured out - he invests in mostly stocks and bonds I think. But I wanted some ideas from other people. Any ideas I can throw at my husband?