Hello Pavel Gutin,
Thank you for your interest in our CMS.
1. I would like to give members the ability to upgrade their membership. The membership would expire after 1 year and would need to be renewed. I am happy to just do this with PayPal.
Nothing to elaborate on here :)
2. I would like to give people the ability to register and pay for events. They may, or may not be members of the site.
Sitefinity is based on Users and Roles. Basically what you can do, is to use the Events module and add an additional Metafield, in which you will store the people's mails, which paid through PayPal for example. Please check the User Manual for more information on adding a new field to a given module.
You can have two roles of people - registered (after paying the membership, create a profile associated with this role), otherwise put the user in another role (if he is registered).
3. Some forum sections need to have an approval process for posting.
Unfortunately this is something on which you will have to work on. We still do not support this functionality in the forums module.
4. I also need a section where everyone will be able to read, but only paid members will be able to host.
This is easy to be done - check step 2. Then you can create pages accessible by users in given role only.
Let us know if you have any further questions.
the Telerik team