Yabasic

Yabasic (Yet Another BASIC) is an interpreter program for a version of BASIC. BASIC is a programming language. BASIC was designed by John George Kemeny and Thomas Kurtz, in 1964. However, Yabasic was born in 1995, 32 years later. Pedro Sá and Thomas Larsen are now developing version 3 of Yabasic. Yasbic is very compact at about 250 kilobytes total length.
How it works.
To write something on the monitor, like Hello World, type print then "YOUR TEXT HERE".
 Print "Hello World"
Study this bit of code:
 10 beep
 20 wait 1
 30 goto 10
The result of this code is:
An audible beep is generated
The program waits for 1 second before going onto the next instruction
It then goes back to the start of the program creating an infinite loop.
This programming language can also be used to create rather complex programs such as one that calculates prime numbers
 print "This program will calculate the prime numbers below the limit"
 input "limit: " limit
 n=2
 do
 for i=2 to sqrt(n)
 if (frac(n/i)=0) then
 notprime=1
 break
 endif
 next i
 if notprime&lt;&gt;1 then
 print n
 endif
 notprime=0
 n=n+1
 if n&gt;limit break
 loop
The "input" command asks the user to input a value which in this case is number that tells the program what number to stop finding prime numbers at.
The 
 do...loop
commands create a loop that can be repeated infinitely.
The
 for...next
commands hold instructions as to what the program is to do while in the loop. 
The
 if...endif
commands tell the program to look for something and if the thing it is looking for is there then it reports back that it is there.