Connectify Hotspot is a great free utility that lets you turn your PC or laptop into a WiFi hotspot. Typical use cases include

• You have an Ethernet connection to your laptop and you can now share it with your mobile phone or tablet.
• You are in a meeting room that has wired Ethernet but no wireless. Now you can simply share your personal WiFi hotspot with everyone else in the room.

If you find other use cases please add a comment to this post.

— update 2012-08-28 21:29 —

My good friend Chris asked why I would want to create a WiFi hotspot on my laptop when I have a perfectly good WiFi hotspot on my Android phone.

The biggest reason is that the PC’s hotspot will share the LAN. That is to say it is on the Intranet not the Internet. In the second use case above I typically need to access internal resources such as file shares and wikis.