XPL
Language and compiler generator system (or TWS: translator writing system) based on language. Derived from PL/I with its syntax, but structure close to C, first release 1968. Descriptions, book, port list, resources, publications list.
http://www.cs.toronto.edu/XPL/

PILOT
Simple interpreted language designed for use in computer-assisted instruction (CAI), 3 implementations, IEEE-standard and open source version exist.
http://rpilot.sourceforge.net/pilot.html

TOP: Table Oriented Programming
Programming that puts tables first. Tables are a vital data representation method. In some applications they are central, almost all you need; far superior to standard APIs: smaller; faster; easier to write, understand, debug.
http://www.geocities.com/SiliconValley/Lab/6888/top.htm

CASL
Language for programming PDAs. Lets you describe a program in terms of graphical elements bound together by your code.
http://www.caslsoft.com/

AML: Anil's Machine Language
Implements a simple, virtual register machine in C++, to make a portable, powerful, efficient way to solve mathematical problems. Its use is not limited to math, but that is its main use so far. Syntax is far easier than normal machine language as the instruction set is easy to learn and understand.
http://www.cris.com/~adhawan/

Quikcode
Free PC implementation of easy, yet powerful procedural IBM mainframe programming language Quikjob. Some uses: scanning files, making reports and quick utilities, converting files. For DOS 5.0 and up, Windows 3.1/95/98, Linux, Stratus VOS.
http://www.quikcode.bizland.com/

Inger
A simple imperative programming language. Description and compiler download. [Open source, GPL]
http://inger.sourceforge.net/

Profan2
Full language with scripting/batch abilities, database development system, built-in ODBC interface, interpreter and compiler. For Windows, common in Germany, easy to make English version. English page on website. [freeware (early version), commercial]
http://www.profan.de/

UniCOMAL
The site supplies and supports MacharSoft version of the COMAL programming language. It's classic imperative interpreted language, similar to BASIC but with a wider range of structures and facilities.
http://www.macharsoft.co.uk/unicomal/unicomal.html

Algol-like Languages
This volume contains historical and foundational material, and works on language design.
http://www.dcs.qmul.ac.uk/~ohearn/Algol/intro.html

The cT Programming Language and Environment
An algorithmic language like C, Pascal, Fortran, and Basic, but greatly enhanced by multimedia capabilities, including easy-to-use support for color graphics, mouse interactions, and even movies in QuickTime or Video for Windows format.
http://vpython.org/cTsource/cToverview.html

Alex
Cross platform rapid GUI development language, runs on many operating systems: Unix (Motif, OpenLook, most others), Windows 32-bit. Lets one set of source code make programs that work across many platforms.
http://www.marsjupiter.com/mambo/index.php?Itemid=83

IMP Compiler
For Imp-77 language on Intel x86 processors, an ALGOL-like high-level language originally designed as the implementation language of the Edinburgh Multi-Access System, developed at Edinburgh University.
http://imp.nb-info.co.uk/

SQR-info.com
SQR is a reporting and database access language. Links to resources and technical information.
http://www.sqr-info.com/

Gema
Home of the GEneral purpose MAcro processor tool, with a binding for the Lua scripting language, named GeL; source and binary distributions.
http://gema.sourceforge.net/

SiMPLE CodeWorks, Inc.
Makes SiMPLE Modular Programming Language and Environment. Beginner-friendly, for kids and adults looking for a new way to have fun with computers. Has full C++ compiler. Descriptions, FAQs, tutorials, tools, forum, games, downloads.
http://www.simplecodeworks.com/

Wikipedia: Imperative Programming
Online encyclopedia article.
http://en.wikipedia.org/wiki/Imperative_programming

Wikipedia: Procedural Programming
Online encyclopedia article.
http://en.wikipedia.org/wiki/Procedural_programming

Frink
A programming language and calculating tool. It tracks units of measure through all calculations, and helps to get the answers right.
http://futureboy.us/frinkdocs/

Leopard
A programming language created solely for beginners.
http://leopardprogramming.wordpress.com/

MCPL
a simple typeless language which is based on BCPL. It makes use of pattern matching somewhat related to that used in ML and Prolog. Some other features come from C.
http://www.cl.cam.ac.uk/~mr10/MCPL.html