Wine is CPU-intensive. If you open up your System Monitor and switch to the Resources tab, you will see that one of the cores is used up entirely. That is especially true of games like Counter-Strike:Source and similar.
Flash should not take up much CPU, and hence should not produce much heat. Though, of course, having many sites open with flashy Flash in them is a bad idea - it all adds up, small or not.
You can try to get the GPU temperature down by using NVidia's proprietary drivers, as it does some fan control and is generally more efficient than the nouveau driver shipped in Ubuntu by default.
And seeing that it is a laptop, both GPU and CPU temperatures can be beaten down with proper air circulation - make sure there's a lot of space under the laptop, or use a fan stand.