Some Examples: Data entry, Billing system, Tracking System, Update Informers, Internet API based ( such as google api, fb api, twitter api, etc ) apps, scrappers, bots.
Specially, i can create a software that can interact with server and also the php code installed on server which will be then used to exchange data with the software ( like chatting software, team work software, which connects many internet users together ).
Don't ask for software like antivirus, video player, designer, etc..
By the way, keep a good habit of contacting before ordering!!