Welcome rudolf!
No problem about english, I'll understand you
About your request: Will you have the birthday informations as content about the event author or as standalone event? The last is difficult, because both (the birthdays and the events) will be in stored in different tables and must combined with a heavy script. I'd tried this some times ago, but ... without a solution
The authors birthdays (if entered by the user) can be displayed. Some questions:
Which format the birthdays should haves? Full birthday (formated like board timeformat) or only the current age of the user? And should an admin be able to enable/disable over ACP the displaying of these informations in the lists?
This should no problem all in all.
Hint: Insert the birthdays in these lists can slow down your board. Every event and birthday more will produce huge traffic on the database whill accessing the eventlists...
OXPUS