My Laptop gets really really hot

Unordered ideas:

• Is frequency scaling active? Install cpufrequtils, ask cpufreq-info for the governor. Setting it to ondemand should help with power consumption.
• Is the fan running? (Do you hear that noise?) If yes, is it blocked by dust? If not, it might be disabled by faulty software. Some sensor drivers can confuse hardware monitoring chips when used simultaneously with acpi drivers. This can lead to turning fans off. The problem is mostly one of the past, but it may still occur when conflicting memory ranges are not declared correctly. Try booting the system without loading hardware monitoring kernel modules (i.e. blacklist them).
• The powertop tool may help you power down other parts of the system reducing the overall heat.
  
• A not-so-official way to reduce heat is to drive your CPU out of specs (also known as undervolting). There are kernel patches for various CPUs. They can reduce heat, but they can also damage hardware.