Switzerland actually has a couple of useful startups that we are using or will use. Teamup
) is one of the best and most straightforward calendars I've come across. It's web-based rather than offering iOS/Android apps, and doesn't itself send reminders (although you can export to iCal), but it is also very clear, easy to use and doesn't offer tons of functions you'll never need. Also at the moment it's still completely free for up to 10 sub-calendars Planyo
) looks to be a very promising online booking system and it seems it's pay-by-use i.e. you only pay when you have customers using it Teamplanbuch
) is great for regular groups needing to organise absences etc. It's designed for sports team practices, music rehearsals etc. but I think you could be imaginative and use it for language classes (CHF 80 a year)
And I assume everyone knows about Doodle
In terms of bookkeeping/invoicing etc., the cloud-based systems seem well-suited to the S part of SMEs. Xero (NZbased) is probably the most comprehensive especially when it comes to multi-currency, but logically is also the most expensive. FreshBooks (US), FreeAgent and Kashflow (both UK) all do much the same thing (you just have to play with them to see which is right for you) and all integrate with other useful solutions.
I also use Xpenditure
) (a Belgian startup) as a Godsend in relation to expenses - never again do I have to enter every expense manually, and it also imports directly into Xero etc.
I should add I have no connection to any of the above except as a happy user sharing the experience of a lot of research!