I had an IVR at home. I made it myself. IVR stands for Interactive Voice Response. That's the machine that answer you when you call the bank, asks you for the account #, pin#, etc and give you balance and other account info.
I was working as a UNIX admin at the time, managing 4 IVRs (Mosaix, Aspect CCS, Nortel Periphonics and can't remember the other one, it was from IBM) handling about 100k calls daily. The cheapest IVR was $60k for the software alone. It was on the cellphone industry, the one that tell prepaid customers their available minutes was the busiest. But the customer care one also took a beating.
I was amazed at how expensive those things were. I had excellent UNIX programming skills (had been UNIX programmer before). I was fluent in C#, C++, Perl, PHP, SQL and all popular shells. I told myself "I can do this... and keep it under $1,000.00". I took the project as a hobby for almost 2 years. I give the box the ability to perform all the functions that the big IVRs at the office did.
At home, I had 12 extensions. Some of them analog and some VOIP phones. All of them going to my IVR. The box had 2 land lines (regular phone lines). Available, there were 3 extra VOIP lines (from VOIP providers on different states), reaching the outside world through a broadband connection.
From inside the house, the system was transparent to a normal person. You just needed to pick up the phone and dial... not need to dial "9" first. But a lot of things happened internally. Long distance calls were routed trough the VOIP lines taking into account what provider had the cheapest rate for that specific number. Local calls were routed via local land lines, always trying to keep the main line free for incoming calls. Through a webpage, you could look at all the phone activity and even make queries. The webpage had a section to handle special numbers rules like, collection agencies going directly to voicemail and different rings for either my friends or my wife's friends.
Calling from the outside, it would first ring as any phone would. But the voice mail was really clever. Based on the called id, you could be routed to a shared house voicemail, my voicemail or my wife's. The voicemail had a 'follow me' option, that would try to reach us on our cellphones if possible. The machine also asked the user if the message was urgent. For urgent voicemail, the system tried to reach me on the cellphone every 30 minutes to let me know I had an urgent message (and play the message too if I choose to hear it).
I even had a "guess where I am" sub-program. I could call home and tell the IVR to call any number, and tell it to dial it using the VOIP lines with any caller ID of my choosing. Meaning, I could call you from my cellphone and make it look (caller id wise) as if I was calling you from the office, your mama's house, or whatever. The last thing I added was a "wake me up" program, to deliver pre-programmed wake up calls.
I printed the whole code once in a book, it was 500+ pages of code. I was using Asterisk hardware, if anybody cares.
So, what's the nerdiest thing you have done?